1. Field of the Invention
The present invention relates to a magnetic powder for a magnetic recording medium which has high coercive force.
2. Description of the Prior Art
Iron oxide of .gamma.-Fe.sub.2 O.sub.3 has been usually used as a magnetic powder for a magnetic recording medium. Recently, a chromium tape has been developed. Thus, cobalt or ferrous ion is adsorbed on chromium dioxide or .gamma.-Fe.sub.2 O.sub.3 to impart high coercive force whereby high density recording has been attained. Recently, an alloy type magnetic powder has been developed and the tendency of the development has been further increased.
In general, a cobalt-doped type magnetic powder and a cobalt-adsorbed type magnetic powder have been proposed to give high coercive force. The cobalt-doped type magnetic powder imparts easily high coercive force but is thermally unstable and has inferior printing characteristics. On the other hand, the cobalt-adsorbed type magnetic powder has low coercive force such as up to 1000 Oe.